A large portion of the bowel runs right under the rib cage. Gas can cause irritation as it passes through the colon. Pain coming from inside the body tends not to be as localized as pain on the skin surface. The pain is often referred to a general area. Chest pains most commonly come from the heart, GI tract or lungs. It can also come from the chest muscles or ribs. People under emotional distress also feel an aching in the middle of the chest.